“Question assumptions.”  Sure, but which ones?  Today's culture is often called skeptical, but about some things it’s not nearly skeptical enough.  It questions assumptions which don’t need to be questioned, and swallows assumptions which really ought to be.

Often people say that the existence of God can’t be proven just because it’s possible to object to the premises of the arguments for His existence.  But it’s possible to object to the premises of any argument, isn’t it?

Whether one can doubt the premises isn’t a good test.  One should ask instead whether the premises are more plausible than what you would have to believe if they’re false, or whether the argument against the existence God leaves us with more troubling and difficult questions than the argument for.

For example, you may object to the Argument to a First Cause by saying that although things in general, like why the milk turned sour, need causes, the whole universe doesn’t need a cause.  But do you really believe that bigger facts are less in need of explanation than smaller ones?

Or you may reject the existence of God because you want to know why there is evil in the world.  But if you reject His existence, are you really uninterested in the converse question, which is why there is good in the world?

In short, we can’t question absolutely every assumption – but sometimes we should question the questions.